Profit & Fee Calculator — FBA Margin Auditor

Turn a messy pile of Amazon fees, COGS, and ad spend into a clean per-unit profit and margin breakdown that tells you exactly where the money leaks — and what to fix first.

When to Use

• Launching a new product: You have a target price and supplier cost, and need to know if the unit makes money after all of Amazon's fees.
• Margin looks wrong: Sales are up but the bank balance isn't, and you need to find which fee line is eating the profit.
• Sourcing decision: Comparing two suppliers or MOQs and need landed-cost-to-net-profit math, not just gross margin.
• Repricing: Deciding whether a price cut still leaves a healthy margin once referral fee and PPC ACoS are layered in.
• FBA vs FBM: Weighing fulfillment-by-Amazon fees against self-fulfillment shipping and labor for the same SKU.
• Storage cost shock: Long-term storage and aged-inventory surcharges hit, and you need true holding cost per unit.
• Return rate bleed: A high-return category is quietly destroying contribution margin and you want the net-of-returns number.
• PPC break-even: Figuring out the maximum ACoS you can run before a campaign turns unprofitable.
• Bundle / multipack pricing: Pricing a 2-pack or 3-pack and need per-bundle fee and margin math.
• Investor / partner reporting: Need a defensible per-unit P&L to show a partner, lender, or accountant.

What You Provide

• Sell price and supplier/unit cost (COGS)
• Inbound freight + duties per unit (or totals to allocate)
• Amazon category, plus product dimensions and weight
• Monthly unit volume and estimated return rate
• Ad spend or target ACoS

What You Get

• A per-unit profit waterfall from sell price down to net profit, every line in $ and % of price
• Contribution margin %, net margin %, and ROI on landed cost
• Your break-even ACoS and how much headroom you have vs current spend
• A sensitivity table showing margin at ±price, ±COGS, and at multiple ACoS levels
• The single biggest controllable cost identified, with the dollar impact of fixing it
• A short, prioritized list of profit levers ranked by dollar impact

Example

Input:

Selling a stainless steel water bottle at $24.99. COGS $4.10/unit, inbound freight + duty $1.35/unit, Home & Kitchen category. 9x3x3 in, 0.8 lb. ~600 units/month. Return rate ~4%. PPC at ~22% ACoS. Is this making money, where's the biggest leak, and what's my break-even ACoS?

Output:

• Per-unit profit waterfall (sell price → fees → landed COGS → PPC → returns → net profit)
• Contribution margin %, net margin %, ROI on landed cost
• Break-even ACoS and headroom vs the current 22%
• Sensitivity table across price, COGS, and ACoS scenarios
• Largest controllable cost named, with the dollar gain from a realistic improvement
• Top profit levers ranked by dollar impact

Why This Skill is Different

• Net-of-returns, not gross: Reserves for returns and recoverable fees, so the margin is the one that actually lands in your account — not the optimistic gross number most calculators stop at.
• Break-even ACoS built in: Ties advertising straight to unit economics, giving you the maximum ACoS you can afford instead of treating PPC as a separate world.
• Sensitivity, not a single number: Shows how margin moves with price and cost swings, so you price with a safety band instead of a fragile point estimate.
• Leak-ranking: Names the single biggest controllable cost and the dollar impact of fixing it, rather than dumping every line equally.
• Defensible assumptions: Every assumed fee rate or tier is stated, so the math is auditable by an accountant or partner.

Who It's For

Amazon FBA and FBM private-label sellers pricing new SKUs; arbitrage and wholesale sellers checking buy-box margin; sourcing and procurement leads comparing suppliers, MOQs, or landed-cost scenarios; brand owners auditing why a profitable-looking catalog isn't generating cash; PPC managers needing a break-even ACoS to set bids; ecommerce finance and ops people building a per-SKU P&L; agency account managers preparing client margin reviews; aggregators doing quick unit-economics diligence; solo founders deciding FBA vs FBM; and anyone repricing after a fee change, freight spike, or competitor price drop who needs to know the floor before they cut.

Disclaimer

This Skill is an AI-assisted estimation tool. It does not access your Amazon Seller Central account, your bank records, or any live fee data, and it performs no transactions. All fee rates, fulfillment tiers, and storage costs are estimates based on the inputs you provide and on publicly known fee structures that Amazon may change at any time — verify every figure against your current Seller Central fee schedule before making pricing, sourcing, or financial decisions. Outputs are not financial, accounting, tax, or investment advice and do not replace a qualified accountant or financial professional. Results are not guaranteed; actual profit depends on factors outside this tool. You are responsible for all decisions made using this output.